1. Field of the Invention
The present invention relates to jacks that are provided with a plurality of contacts along a plug insertion hole formed in a body, the contacts including tip contacts that contact a tip electrode at a front end of a plug that is inserted onto the plug insertion hole, and intermediate contacts that contact a ring electrode at an intermediate location of the plug.
2. Description of the Related Art
Conventionally, the jacks disclosed in Japanese Patent No. 2633258 and Japanese Patent Application Publication No. JP 2001-217053A are known as jacks similar to the one disclosed in the present invention. Among these pieces of related art, the former is configured such that when a multipolar plug is inserted into a jack unit (corresponding to the body in the present invention), a conductive state is established by bringing a plurality of connection plug contacts (a concept including the tip electrode and the ring electrodes of the present invention) formed on the multipolar plug into contact with a corresponding plurality of contact terminals (corresponding to the contacts in the present invention) inside the jack unit. Moreover, the latter of these pieces of related art is configured such that the inside of a jack unit (corresponding to the body in the present invention) is provided with a ring contact piece and a tip contact piece (corresponding to the tip contact of the present invention) in which a pair of tip electrodes are formed at both ends of a plate-shaped linking member, whereby, when a unipolar plug is inserted into the jack unit, the tip electrodes at the front end of the unipolar plug are contacted in an embracing fashion by the tip contacts, and the ring electrode at an intermediate position of the unipolar plug is contacted by the ring contact piece, thereby achieving a conductive state.
Focusing on the tip contacts that contact the tip electrode at the front end of the plug, in the former of these pieces of related art (Japanese Patent 2633258), one end portion of the connection terminal disclosed in the drawings of this publication is supported by the jack unit, and the other end portion is configured with a relatively long length, so that it is used as a contact for the plug. When the connection terminal is supported in this manner, it is possible to utilize the elastic deformation of the entire material of the connection terminals, and the contact force does not decrease even when repeatedly inserting and pulling out the plug, so that a favorable performance is attained in which a contact force of substantially predetermined strength is maintained. However, if slackening or loosening occurs at the site at which the connection terminal is supported by the jack unit, then an adequate contact force may not be attained, which may lead to a bad contact, thus leaving room for improvement. To address this problem, with a jack having a structure in which a pair of tip contacts contact the tip electrodes in an embracing fashion as in the latter of the pieces of related art (JP 2001-217053A), such that the tip electrode is embraced by the pair of tip contacts, the state of the pair of tip contacts embracing the tip electrode is maintained, even when slackening or loosening of the support portion with respect to the jack unit occurs, so that a reliable contact state can be anticipated.
In these kinds of jacks, even though there is a need for forming the tip contact piece in a compact manner, in view of keeping the overall jack from becoming bigger, the tip contact piece is arranged at an end location of the jack, so that it is difficult to design a structure in which an elastic spring force is attained when used for long spans of time, thus leaving room for improvement. In particular, with a tip contact piece that is made small, as in the latter of the pieces of related art, when the tip contact piece is deformed greatly, such as when a large prying force is applied from the plug, the tip contact piece may be ultimately enter a state of plastic deformation, so that a favorable performance was difficult to realize.
It is an object of the present invention to efficiently configure a jack with which the tip electrode at the front end of a plug can be reliably contacted and a favorable conductive state established even when used over a long period of time, without making the jack bigger.